Electric switch construction



Jan. 11, 1938.

M. GUETT E-r A1. 2,105,415 ELECTRIC SWITCH CONSTRUCTION Filed Aug. 4, 1954 2 sheets-sheet 2 :QI /43 77 42 [flip-lll] 40 QUI@ A @a .i 1%;

INVENToRs MONROE GUET ERT H.BENT

T51-15 www MM- 25 switch box.

Patented Jan. 11, 1938 I UNITED STATES f PATENT OFFICE ELECTRIC SWITCH CONSTRUCTION Application August 4,

18 Claims.

This invention relates to electric switches. More particularly it relates to contact assemblies for electric switches and means for holding contact assemblies within an insulating cas- 5 ing or shell. Recently a demand has'arisen for small size electric wiring devices such as switches, attachment plug receptacles, pilot lights, push buttons and the like. Electric Wiring devices of rthe kind just mentioned as heretofore manufactured were of such construction that it is impractical merely to reduce their dimensions in order to make those devices small enough so that several of them could t in the space originally intended for one device. It has therefore become necessary to rind new ways of constructing such devices and particularly electric switches so that their parts might be enclosed within a small casing in order that several such casings might be placed within the space originally used to accommodate one electric wiring device.'

Accordingly it is an object of our invention to construct electric yswitches in such a manner as to reduce'their dimensions and enable several of them to be accommodated within a single gan Another object of our invention is to provide an inexpensive and sturdy contact assembly for an electric switch which assembly may be easily constructed and quickly put in place and firmly 30 held there. f

Another object of our invention is to provide a contact assembly for a double pole electric switch in which a pair of terminals and contacts associated therewith may be mounted as a unit in each end of a switch casing or shell.

Another object of our invention is to provide a switch into the opposite ends of which interchangeable units carrying various combinations of wire terminals and switch contacts may be mounted to adapt the switch for use as an ordinary double pole switch, or in a three way'circuit or a four way circuit;

Another object cf vour invention isV to provide an inexpensive and sturdy means tosecure and hold the contacts in place within an insulating yswitch casing in a rigid manner without ther use of screws4 or straps which pass acrossthe rear face of the switch. j

`Other objects andadvant'ages of our invention will become apparent as it is described in connection with the accompanying drawings. In the FigureV 1 is a sideelevation view of a'switch casing partly brokenaway, and a contact assetti? 1934, Serial No. 738,523.'

bly formed according to the principles of our invention. y

Figure 2 isan end elevation view of the embodiment of our invention shown in Figure 1.

Figure 3 is a bottom view of the embodiment of our invention shown in Figure 2.

Figure 4 is a bottom view looking into the interior of the switch casing or shell shown in Figure 1, when the shell is empty.

Figure 5 is a longitudinal section view through the embodiment of 'our invention shown in Figure l, the section being taken along the line 5-5 of Figure 4.

Figure 6 is a transverse section view ofthe embodiment of my invention shown in Figure 1, the section being taken along the line 6 6 of Figure 5.

Figures 7 and 8 are perspective views of une contacts which are placed at opposite ends of the insulating casing in the embodiment of our invention shown in Figures 1 to 6.

Figure 9 is an end elevation View of another form of our invention which is adapted for a dou ble pole switch. f

Figures 10 and 11 are elevation views of the front and back of the contacts and their mounting which are placed at one end of the embodiment of ourinvention shown in Figure 9.

, Figure 12 is an end elevation View of the opposite end of the embodiment of our invention which is shown inl Figure 9.

Figures 13 andV 14 are views of opposite sides vof the contacts and their mounting which are mounted in said opposite end of the switch cas- 9yto l'ljthe section :being taken on line {8f-|8- of Figure 17. l y A, Y

Referring now to the drawings, the switch casing is of insulating material Iand comprisesa hollow'fshellil of rgenerally ,rectangular prismatic shape having aY reducedv neck 2 atits topwith an f 'opening lliftherenfor a switch operating handle or lever 4.A 'I'hegjcasingfmay bemounted vupon a supporting strap (not shown)y inthe manner illustrated" in Vv,the patent i of 1 Monroe Guett No.

1,909,270, patented May 16, 1933. For the sake of clearness, the switch frame and all the moving parts of the switch mechanism carried thereby have been omitted from the drawings since these parts and this mechanism per se form no part of the present invention. It will be understood, however, that any suitable switch mechanism may be provided for actuating a bridging contact to connect and disconnect the xed contacts hereinafter to be described. Preferably, a lever operated type of switch for snapping the bridging contact between open and closed position is used.

The switch casing or shell I has formed at each end at the bottom edge, arcuate recesses 5 and 6 to give access to binding screws 1 and 8, which are threaded into metallic terminal members 9 and I0, within the shell, stationary switch contacts II and I2 being mounted on said members.

The terminal members 9 and I0 are somewhat similar in shape but are not identical. Each terminal member has at its lower end opposed laterally extending arms 9a and Na respectively, the distance between the ends of these arms being equal to the distance between the inside faces of the longitudinal walls of the switch casing I, so that the engagement between the ends of the arms and the, walls of the casing prevent lateral movement of the terminal members. Each terminal member also has at its lower end an extension 9e and Ie respectively, which is adapted to be engaged by the edge of a rear plate I4 of insulating material, the outline of which'preferably corresponds with the outline of the bot-r tom of the insulating casing except as to the recesses or cut away portions I5, It, into which the extensions 9e and Ile nt snugly. The engagement of the rear insulating plate I4 with these extensions prevents movement of the terminal Imembers longitudinally of the casing.

Each terminal member has arms 8c and Ic respectively extending from the body portion of the terminal member toward one and the same wall of the switch casing. The ends of these arms abut the side of thev casing and tend to prevent rocking of the terminal members and thus tend to hold the terminal members in position. Preferably the top edges of the arms 9c and Illc abut the portion of the interior of the top of the switch casing. Upon one of the arms IUa, is mounted a fixed switch contact I2 made of thin sheet metal reversely bent into U-shape and positioned so as to be perpendicular to the plane of the terminal member I0. In the central portion of this stationary contact, there is an aperture through which extends a finger Isf oi a narrow insulating plate I8, the lower end of which is received between the reversely bent portions of the stationary contact I2. The plane of this plate is perpendicular to theplane of the terminal member I0. The lower extending finger I8f also passes through an aperture provided therefor in the reary plate I4 of the casing. The insulating plate I 8 extends upwardly beyond the end of the arm IIIc and has a nger I8a in extension of its upper end and'fitting within the recess I9 provided thereforin the top wall of the casing. The whole of the upper end of the insulating plate I8 flits intoa larger recess 20 which is provided in the upper wall of the switch casing. The recess I9 is deeper and is encompassed by the recess 20. The engagement of the iingers IBa and I8f with the top wall of the casing and the rear plate I4 holds the insulating plate I8 rmly in position, and holds terminal I0 against the end wall of the casing.

The terminal member 9 has a stationary contact I I mounted upon its upper `arm 9c and has an insulating plate 22 which passes between the reversely bent portions of the contact Il and which has a finger 221 extending from the lower end into an aperture provided therefor in the rear plate I4. The whole of the upper end of the insulating plate 22 fits into a recess 24 provided in the top wall of the switch casing and has a finger 22a extending beyond the end of the plate into a deeper recess 25 which is encompassed by the recess 24. The purpose and function of the plate 22 is similar to that of the plate IB.

The movable contact I1 of the switch diagrammatically shown in Figure v5, may be made of a.

pair of identical laminated sheet metal stampings with spread ends which straddle the stationary contacts and wipe over the outside surfaces of each of the reversely bent parts of the stationary contacts I I and I2. When the movable contact which preferably is rotatably mounted moves away from the stationary contacts the surfaces of the movable contact wipe over the'surfaces of the insulating plates Iband 22 thus tending to,cool and quickly extinguish any arc which may be drawn between the contacts as they separate.

In order to hold the rear plate I4 to the switch casing thin metallic straps 21, 28 run down the side of the casing from the ledge or shoulder 2l formed at the neck 2 and the boch' of the casing, and have their lower ends turned around the edge of the plate I4 and have fingers 21j, 28! respectively extending into apertures-in and near the edge of the rear plate. 'I'he top ends of the straps 21, 28 have laterally extending arms 21a,

'28a extending into recesses 29 cut in the shoulder or ledge of the casing adjacent the neck 2. Preferably these recesses are of wedge shape and widen as they proceed inward so that when the arms 21a and 28a are spread against the sides of the recesses the straps 21 and 28 will be held from moving away from the sides of the casing. In order to economize on space and to present a smooth side surface for the switch casing, grooves or paths 30 are sunk in the sides of the casing' for the straps 21 and 28 so that the surface of the casing and the surface of the strap will be in the same plane. .Thus we have provided a simple inexpensive way to hold the rear plate to the switch casing and to hold the contacts and wire terminals xedly in position without the use of any screw, rivet or similar part such as has been commercially used heretofore.

The construction we have described thus far is suitable for a single pole snap switch, but the principles of the invention may also be applied to a double pole snap switch as will be apparent ,from the description of the embodiment of our lan 'aperture 46 is provided directly above the recess 44 for another binding screw 41. The screws 45 and 41 are threaded into terminal plates 48'and 49 which are mounted upon a rectangular insulating plate 50 whose width is approximately the same yas the distance between the inside walls of the switch casing. Engagement of the sides of the plate 58 with the inside walls of the casing prevent the lateral movement of the mounting plate 58 within the casing. The shapes of the terminal plates 48, 49 may be observed best by study of Figures 10 and l1. On the opposite side of the mounting plate 58 from the terminal plates 48 and 49 there are four stationary contacts each being of thin sheet metal reversely bent into U-shape, and each provided with fingers extending through apertures in the mounting plate 58 and the lingers of three of the contacts extending into corresponding apertures formed in the terminal plates 48 and 48, the ends of the ngers being peened over to hold the contacts in permanent engagement with the terminal plates or mounting plate 58. One contact is positioned in each of the fouricorners of the rectangularly shaped mounting plate 58. The stationary contact (which in Figure 1l is at the upper right hand corner of the mounting plate) engages and is in electrical connection with the terminal plate 48. The stationary contact 52 (which is in the upper left hand corner of the mounting plate) is in electrical contact with and engages the terminal plate 48. The stationary contact 53 (which is in the lower right hand corner of the mounting plate) engages with and is in electrical connection with the terminal plate- 48. Thus the stationary contacts 52 and 53 are permanently and electrically connected through the terminal plate 48. The stationary contact 54 which is in the lower left hand corner of the mounting plate is electrically connected by a thin strip of copper 55 with the stationary contact 5I, this strip of copper 55 being on the opposite side of the mounting plate from the terminal plates 48 and 49 and thus is insulated from the terminal plate 48.

A plate 68 of insulating material, rsimilar to the mounting plate 58 and adapted to be mounted 58, has mountedupon one side of it metal terminal plates 58, 59 and on the other side stationary switch contacts 6I, 62, 63, 64, these stationary contacts being similar in size and shape to the stationary contacts 5I to 54 inclusive hereinbefore described. The stationary contacts are mounted upon the mounting plate 68 and secured to the terminal plates 58 and 59 in manner and position similar to that described in connection with mounting plate 58. The relative size and shape of the terminal plates 58 and 59 may be observed by examination of Figure 13 from which it will be noted that contacts 6I and 63 are permanently electrically connected to the terminal plate 58 and contacts 62 and 64 are permanently electrically connected to terminal plate 59. The terminal plates 58 and 58 are provided with binding screws 65 and 61 respectively,v these screws being accessible through a recess 66 and an aperture 68 respectively in the end of the casing opposite to the binding screws 45 and 41, the arcuate recess 66 being similarly placed to the recess 44 and the aperture 68 being above but slightly olf- ,set from the recess 66.

Narrow insulated plates 18, 1|, 12 and 13 for arc quenching are held in position by stationary contacts S2- 54, 5l-53, {i2-54 and ISI- '33 respectively in a. similar manner to the plates I8 and 22 described in connection with the modification shown in Figures l to 8. The ends of each of these plates 18-13 are provided with extending fingers which engage in apertures in the rear plate 16 of the switch and recesses '11, 18, 19, 88 in the inside of the top wall of the casing in similar manner to the insulating plates I8 and 22 whereby they are held xedly in position, and they hold the mounting plates 58, 68, in position. Downwardly directed extensions 48e and 59e are providedon the terminal plates 48 and 59 and these extensions engage with the recesses 88 and 82 formed in the ends of the rear insulating plate 16 to hold the contacts against longitudinal movement in the casing in a manner similar to that described in connection with the modication shown in Figures 1 to 8.

Metal securing straps 21. and 28 are used to hold the rear plate 16 to the casing 48 in a manner like that described in connection with the modication shown in Figures 1 to 8.

In the double pole switch of Figures 9 to 18 it is necessary to use two bridging contacts, one located on each side of whatever conventional operating mechanism is used to move the switch contacts; but in the single pole switch of Figures 1-8 only one of the bridging contacts need be employed, though the same operating mechanism can be used.

A suflicient number of contacts are provided in the modification just described to use the switch as a four-way switch. It will be apparent,`

however, that a person skilled in the art may by eliminating one or more of these contacts use the switch as a three-way or a common double-pole switch, it being remembered that suitable wiring changes for each type of switch will have to be made in the circuit in a manner well known to those skilled in the art. Thus units may be made up with the requisite number of contacts and inserted to fulfill the requirements of the particular usage to which the switch is to be subjected.

From the foregoing it will be apparent that the principles of our invention are applicable to single pole, double pole, three way or four way switches and therefore we do not limit our invention except as appears in the following claims to any one type of switch. Obviously nism and apertured in the front for switch opervlengthwise of the casing by the side walls of the casing but engaging at its top with the inside of the top wall of the casing and having an extension reaching beyond the plane of the back of the casing for holding said device in place, a

back plate for the casing engaged by said extension, and means holding said plate to said casing. y

2. In an electric switch, an insulating casing open at the rear for insertion of switch mechanism and apertured in its front for switch operating means, combined contact and wire terminal means including an insulating plate whose area is approximately equal to that of the inside of the end of the casing, the wire terminal portion of said contact and terminal means being accessible through a recess in the end of said casing,

said contact and terminal means being unre- F strained against movement lengthwise of the casing by the side walls of the casing but err` gaging at the top with the inside of the top Wall of the casing and having an extension reaching beyond the'plane of the back ofsaid casing for holding said contact and terminal means in place, a back plate for the casing engaging said extension, and means holding said plate to said casing.

3. In an electric switch, an insulating casing open at the rear for insertion of switch mechanism and apertured in its front for switch operating means, an assembly comprising insulating means having contacts and wire terminals mounted thereon, said terminals being accessible through recesses in the ends of said casing, said assembly being unrestrained against movement lengthwise of the casing by the side walls oi the casing but engaging the inside of the top wall of said casing, one of said wire terminals having an extension reaching beyond the plane of the back of said casing, and a back plate for said casing to hold said assembly in place, and means holding said back plate to said casing.

4. In an electric switch, an insulating shell, contact and wireterminal members at opposite ends of said shell, having terminal screws accessible through recesses in said ends, a rear plate for said shell engaging with extensions oi' said contact and terminal members to prevent lateral and in-and-out movement of said contacts, and separate metal straps on opposite sides of said shell engaging with the edges of said rear plate having laterally extending arms bent to lie in a recess in the top portion of said shell to hold said rear plate in pla'ce, the inner portion of said recess being larger than the outer.

5. In an electric switch, an insulating shell, contact and wire terminal members `at opposite ends of said shell, having terminal screws accessible through recesses in said ends, a rear plate for said shell engaging with extensions of said contact and terminal members to prevent lateral and in-and-out movement of said contacts, and a ledge' around the top of said shell, and separate metal straps on opposite sides oi said shell engaging with the edges of said rear plate and with said shell at said ledge to hold said rear plate in place, the sides of said shell being provided with channels in which said straps lie.

6. In an electric switch, an insulating shell, contact and wire terminal members at opposite ends of said shell having terminal screws accessible through recesses in said ends, a rear plate for said shell engaging with extensions of said contact and terminal members to prevent lateral and in-and-out movement of said contacts, and a ledge around the top of said shell, and separate metal straps on opposite sides of said shell having reversely bent Aends engaging the edges of said rear plate and laterally extending ears bent to seat-in recesses in said ledge, to hold said rear plate in place.

'7. In an electric switch, an insulating casing, open at the rear for the insertion of switch mechanism and apertured in its front face for switch operating means, combined contact and wire terminal means, the wire terminal portion of said contact and terminal means being accessible through a recess in the end of said casing, said contact and terminal means engaging at the top with the inside of the top wall o! said casing and having an extension reaching beyond the plane of the back of said casing, a back plate for the casing engaging said extension to hold said terminal means in place, arc quenching means in engagement with said fixed contacts and interlocking with said rear plate and casing, whereby said arc quenching meansv is ilxed in position, and means holding said back 'plate to/said casing.

Y8. In an electric switch, an insulating casing, open at the rear for the insertion of switch mechanism and apertured in its front face for switch operating means, combined contact and wire terminal means, the wire terminal portion of said contact and terminal means being accessible through a recess in the end of said casing, said contact and terminal means engaging at the top with the inside of the top wall of said casing and having an extension reaching beyond the plane of the back oi said casing, a back plate for the casingl engaging said extension to hold said terminal means in place, an insulating plate engaged with the contact portions of said contact and terminal means and having its ends engaging with said back plate and said casing whereby said insulating plate is fixed in position, and means holding said back plate to said casing.

9. In an electric switch, an insulating casing, open at the rear for the insertion of switch mechanism and apertured in its iront face for switch operating means, combined contact and wire terminal means, the wireterminal portion of said contact and terminal means being accessible through a recess in the end oi said casing, a back plate for said casing, an insulating plate engaged with the contact portions of said contact and terminal means and lying in a plane perpendicular to the terminal portion of said contact and terminal means, said insulating plate engaging at its ends with the back plate and the inside of the top wall of the casing to hold said contact and terminal means against the end wall of the casing, and means holding said back plate to said casing.

10. In an electric switch, an insulating casing open at the rear for the insertion of switch mechanism and apertured` in its front face for switch operating means, combined contact and wire terminal means, the wire terminal portion of said contact and terminal means being accessible through a recess in the end of said casing, said contact and terminal means having an extension reaching beyond the plane of the back of said casing, a back plate for the casing engaging said extension, an insulating plate engaged with the contact portion of said contact and terminal means and having its ends engaging with said back plate 'and the inside of the top wall of said casing whereby said insulating plate is iixed in position and holds said contact and terminal means against the end wall of the casing, and means holding saidback plate to said casing.

1l. In an electric switch, an insulating housing having iront, back, side and end walls, at least one of.said walls being separately formed from the remainder and forming a cover for said housing, said cover when removed permitting insertion of a switch mechanism into said housing, a combined contact and wire terminal device at an end of the housing, the wire terminal portion of the device being accessible through an opening in the end wall, said device being unrestrained against movement lengthwise of said housing by the side walls but engaging at its top with the front wall and at its bottom with a recess in the back wall whereby said device is held in place, and means holding said housing and cover together.

12. In an electric switch, aninsulating housing having iront, back, side and end walls, at least one of said walls being separately formed from the remainder and forming a cover for said housing, said cover when removed permitting insertion of a switch mechanism into said housing, combined contact and wire terminal means including an insulating plate whose area is approximately equal to that of the inside of the end of the housing, the wire terminal portion of said contact V and terminal means being accessible through an opening in the end of said housing, said contact and terminal means being unrestrained against movement lengthwise of the housing by the side walls of the housing but engaging at the top with the top wall and having an extension reaching into a recess in the back wall for holding saidy contact and terminal means in place, and meansholding said cover and housing together.

13. In an electric switch, an insulating housing having front, back, side'and end walls, at least one of said Walls being separately formed from the remainder and forming a cover for said housing, said cover when removed permitting insertion of a switch mechanism into said housing, an assembly comprising insulating means having contacts and wire'v terminals mounted thereon, said terminals being accessible through openings in the ends of said housing, said assembly being unrestrained against movement lengthwise of the housing by 14. In an electric switch, an insulating housing having front, back, side and end walls, at least one of said walls being separately formed from the remainder and forming a cover for said housing, said cover when removed permitting insertion of a switch mechanism into said housing, a combined contact and wire terminal means, the Wire terminal portion of said contact and terminal means being accessible through an opening in the end of the housing, said contact and terminal means engaging at the front with the front wall of the housing and having an extension reaching into a recess in the back wall, arc quenching means in engagement with the xed contact means and interlocking with said cover and housing, whereby said arc quenching means is iixed in position, and means holding said cover and housing together.

15. In an electric switch, an insulating housing having front, back, side and end walls, at least vone of said walls being separately formed from the remainder and forming a cover for said housing, said cover when removed permitting insertion of a switch mechanism into said housing, combined contact and wire terminal means, the wire `terminal portion of said contact and terminal means being accessible through an opening in the end of the housing, said contact and terminal means engaging at the front with the front wall of the `housing and having an extension reaching into a recess in the back wall, an insulating plate engaged with the contact portions o1 said contact and terminal means and having its ends engaging said cover. and housing whereby said insulating plate is held xed in position, i

terminal portion of said contact and terminalmeans being accessible through an opening in the end of the housing, said contact and terminal means engaging at the front with the front wall of the housing and having an extension reaching into a. recess in the back wall, an insulating plate engaged with the contact portions of lsaid contact and terminal means and lying in a plane perpendicular to the terminal portion of said contact and terminal means, said plate engaging at its ends with the front and back walls of said housing t-o hold said contact and terminal means against the end wall of the housing, and means holding said cover and housing together.

17. In an electric switch, an insulating housing y having front, back, side and end walls, at least one of said walls being separately formed from the remainder and forming a cover for said housing, said cover when removed permitting insertion of a switch mechanism into said housing, combined contact and wire terminal means, the Wire terminal portion of said contact and terminal means being accessible through an opening in the end of the housing, lsaid contact and terminal means having an extension reaching into a recessin the back wall of said housing, an insulating plate engaging at its ends with the front and back walls of said housing to hold said contact and terminal means against the end wall of the housing, and means holding said cover and housing together.

18. In an electric switch, an insulating housing having front, back, side and end walls; at least one lof said Walls being separately formed from the remainder and forming a cover for said housing, said cover when removed permitting insertion of a switch mechanism into said housing, an assembly comprising insulating means having contacts and wire terminals mounted thereon, said terminals being accessible through openings in the ends of said housing, arc quenching means in engagement ith the said contacts and interlocking with said cover and housing whereby said arc quenching means is xed in position and impedes movement of said assembly lengthwise of said housing, and means holding said cover and housing together.

MONROE GUET'I'. ROBERT H. BENTLEY.` 

